With the rapidly expansion of the market for laptop computers, mobile phones, electric vehicles, and the like, a secondary battery having a high energy density is required. Examples of a method for obtaining a secondary battery having a high energy density include a method in which a negative electrode material having a large capacity is used, and a method in which an electrolyte liquid having excellent stability is used.
Patent document 1 discloses using a silicon oxide or a silicate as a negative electrode active substance of a secondary battery. Patent document 2 discloses a negative electrode for a secondary battery which has an active substance layer containing a carbon material particle that can absorb and desorb lithium ion, a metal particle that can be alloyed with lithium, and an oxide particle that can absorb and desorb lithium ion. Patent document 3 discloses a negative electrode material for a secondary battery which is formed by coating the surface of a particle, which has a structure in which a silicon fine crystal is dispersed in a silicon compound, with carbon.
Patent document 4 discloses using a negative electrode that can absorb and desorb lithium and using a nitrile compound having a carbon-carbon unsaturated bond in an electrolyte liquid.
Patent document 5 discloses using an electrolyte liquid which contains a nitrile compound having a specified structure.
Patent document 6 discloses using an electrode active substance which contains a phthalimide compound.
Patent document 7 discloses using an electrolyte liquid which contains a phthalic imide derivative.
Patent document 8 discloses using an electrolyte liquid which contains a compound consisting of benzimidazolone or benzoyleneurea, or a derivative thereof.
Patent document 9 discloses using an electrolyte liquid which contains pthalazone or a derivative thereof.
Patent document 10 discloses using an electrolyte liquid which contains a compound represented by a predetermined formula.
Patent document 11 discloses using an electrolyte liquid which contains a polymer particle having a carbodiimide unit and having an average particle diameter of 10 μm or less as an additive for a battery.
Patent document 12 discloses using an electrolyte liquid which contains a polymer of an uretonimine compound represented by a predetermined formula.